Cordless Screwdriver Hydraulic Tool for High-Force Pressing
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Solution Overview
Problem
Existing hydraulic tools for driving pulling and/or pressing devices are complex and expensive to produce, requiring a compressed air connection and being less efficient in generating high pressures with a compact design.
Innovation Solution
A hydraulic tool that attaches to a cordless screwdriver, utilizing a hydraulic pump driven by the screwdriver's drive shaft, with a high hydraulic transmission ratio to generate high pressures through an oscillating pump piston and differential working piston, allowing for compact and powerful operation without the need for a pneumatic system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If a pneumatic/hydraulic pump principle is used to generate high pressures in a small space, then high pressure and power are achieved, but the tool becomes complex and expensive to manufacture
Solution Approach 1:
The patent uses a hydraulic pump system with a pump piston and working piston connected through hydraulic fluid. The pump piston moves back and forth to pump hydraulic fluid into the working chamber of the working piston, generating high pressure (over 500 bar) that is transmitted through the hydraulic fluid to the working piston, which then generates high tensile or compressive forces (over 10,000 N, preferably over 50,000 N).
Solution Approach 2:
The hydraulic tool is divided into distinct functional components: a drive shaft that can be attached to a screwdriver, a hydraulic pump with a pump piston, a working piston with a larger pressurized area, and a coupling for attaching setting or pressing tool attachments. This segmentation allows for easier manufacturing and assembly compared to integrated pneumatic systems.
2Force
If a pneumatic system is used to generate high pressures, then high forces are achieved, but a compressed air connection is required which reduces portability
Solution Approach 1:
The hydraulic pump is self-contained and can be driven directly by the screwdriver's motor without requiring an external compressed air supply. The pump piston is moved by the drive shaft, which converts the screwdriver's rotational motion into the oscillating motion needed to pump hydraulic fluid, making the system portable and independent of external pneumatic infrastructure.
3Force
If a high hydraulic transmission ratio is used to generate high pressures with a small power tool, then high forces are achieved, but the design becomes more complex
Solution Approach 1:
The working piston has a larger pressurized area than the pump piston, creating an asymmetric hydraulic transmission system. This area difference (with the working piston being at least twenty, preferably fifty, and preferably up to 100 times larger in terms of hydraulic fluid-actuated area) provides the mechanical advantage needed to generate high forces from the smaller pump piston movements.
Solution Approach 2:
The pump piston moves in an oscillating manner rather than a continuous rotational motion, dynamically converting the screwdriver's rotational drive into reciprocating pump action. This oscillating motion is achieved through an eccentric mechanism where an eccentric shaft rotates in ball or needle bearings, providing a simple yet effective way to generate the required piston movement.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The tool achieves high tensile or compressive forces up to 50,000 N with a compact design using fewer components, eliminating the need for a pneumatic system and making it more affordable and user-friendly.
Implementation Method 1
a hydraulic pump which is driven by the drive shaft and which pumps hydraulic fluid into the working chamber of a working piston
Implementation Method 2
The working piston has a larger pressurized area than the pump piston... even with a comparatively small power tool, high pressures in the working chamber of the working piston and thus correspondingly high tensile or compressive forces can be generated
Data Source
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AI summary
The invention relates to a hydraulic tool for driving a pulling and/or pressing device, comprising a drive shaft which can be mounted on a screw driver, wherein a hydraulic pump which pumps hydraulic fluid into the working chamber of a hydraulic working piston can be driven via the drive shaft. The hydraulic tool can be designed in particular as an attachment for riveting or punching for a cordless screw driver.